The present invention relates generally to a gel cushioned interface and a method of making a gel cushioned interface made of polymer material with heat resistant and electrically conductive neural receptors housed strategically within and potentially raised slightly above the inner surface of the polymer material to be worn over a limb or body surface for the purpose of conducting and/or receiving impulses through the interface.
The use of myoelectrics in the orthotics and prosthetics field started with the basic use of a conductive metal dome placed on a user's particular muscle group to pick up neural signals from nerve endings through the skin. With such a system, when the user would fire the bicep muscle, for example, the dome would pick up the signal and send it to the powered prosthesis telling it to create flexion in the prosthetic elbow. Many metal domes would be affixed to the skin of the end user externally and hard-wired (sometimes long distances) into the powered prosthetic device so that the user could fire off certain muscle groups to control functionality of the prosthesis.
More recent improvements to myoelectrics in the field involve using a series of metal domes that are punctured through and embedded in an otherwise traditional liner interface after the molding process, that are then connected to a CPU using external wires that control the powered prosthesis. Concurrently, other developments are taking place where metal electrodes are actually implanted into the user's pectoral muscle and hardwired to a CPU for cognitive control over the prosthesis.
The process of surgically inserting metal domes into a user is obviously a very invasive procedure that many potential users are unwilling to undergo. The post-molding process of puncturing holes into a liner to insert metal domes is also a difficult process that is time consuming and jeopardizes the original liner's structural integrity and durability. Thus, the need in the market exists for an interface liner that contains electrically conductive receptors that can make the appropriate amount of skin contact necessary to reliably pick up electrical impulses from very specific points on the user while also containing a means of transferring these impulses to a central processing unit.
One attempt that has been made to satisfy this need is disclosed in USPGPUB 20090216339 A1 to Hanson, et al., incorporated herein by reference. As best illustrated in FIG. 1 (10) or FIG. 2 (20), Hanson suggests affixing “domes” made of conductive silicone onto existing prosthetic liners after the molding process has taken place. Hanson focuses on the silicone dome's ability to create total contact on the skin surface, while also being properly affixed to the liner with an appropriate adhesive such as RTV silicone for silicone liners or moisture-activated urethane for urethane liners to form a more secure “butt joint” to hold the domes securely in place once they are added to the liner. USPGPUB 20100114238 A1 to Muccio incorporated herein by reference discloses a prosthetic liner, as best illustrated in FIGS. 1 and 2, having stimulation electrodes made of conductive hydrogel 105 integrated into the liner material during the molding process that are designed to be flush with the skin 106 on the inside of the liner and connected to a CPU by silver fabric conductors 103. USPGPUB 2010/0318195 A1 to Kettwig, et al. incorporated herein by reference discloses an orthopedic interface having electrically conductive coatings 23 on the inner fabric surface of the liner.
While these ideas seek to address the need for improving end user comfort while not jeopardizing functionality, they fail to address the need for a single off the shelf product that combines the manufacturability of having the electrodes molded into the inner material during a “one shot” manufacturing process while still allowing those same domes to provide an adequate amount of compression on the localized skin necessary to get a consistent myoelectric signal.